There are many safety syringe designs available today. Some of these designs have a sleeve or sheath that will cover the needle after it has been used. Some typical designs with sleeves or sheaths are Z. M. ROEHR et al U.S. Pat. No. 3,008,570, Z. M. ROEHR U.S. Pat. No. 3,107,785, BARTNER, et al U.S. Pat. No. 3,895,633, G. K. Burke U.S. Pat. No. 3,306,291, GYURE et al U.S. Pat. No. 4,300,678, WINSTEAD HALL U.S. Pat. No. 4,356,822, SAMPSON U.S. Pat. No. 4,425,120, LARSON U.S. Pat. No. 4,639,249, HARBAUGH U.S. Pat. No. 4,655,751, STRAUSS U.S. Pat. No. 4,664,654, BRAGINETZ U.S. Pat. No. 466,435, SPENCER U.S. Pat. No. 4,702,738, MILORAD U.S. Pat. No. 4,702,739, SPENCER U.S. Pat. No. 4,801,295, PONCY U.S. Pat. No. 4,816,022, and HUGHES U.S. Pat. No. 4,840,619.
Other designs have a retractable needle such as Weltman U.S. Pat. No. 3,306,290, And DENT U.S. Pat. No. 4,392,859. These designs do not have a means whereby the needle is extended from the syringe and held in place in a positive and rigid position in order to first inject the needle prior to injecting the medication. Still other designs have methods of bending the needle to render it harmless after the medication has been injected. Both of these designs have one major purpose and that is to prevent the spread of infectious diseases such as aids, hepatitis or other diseases from an accidental injection with a contaminated needle into others after the needle of the syringe was inserted into a patient with the above mentioned diseases. These various designs all work up to a degree, but they all fall short of thier intended purpose during the act of covering the needle, or removing the needle which requires two hands.
All of these designs require at least two hands to operate. The use of two hands to cover the contaminated needle is most unsatisfactory in that during the act of placing a second hand on the syringe the person holding the syringe in one hand may be bumped and accidentaly inject the needle into their other hand before it can grasp the syringe. Other accidental jabbing or injections can happen in an ambulance where just as a person tries to grasp the contaminated syringe, the ambulance can hit a bump in the road causing the person holding the syringe to accidentally stick another person or themselves with the contaminated needle. The need has developed for a syringe that will cover the contaminated needle with the use of only one hand.
All of these designs also combine the needle cannula with the syringe and therefore cause a major inventory and storage problem. At present, needles cannulas are fixed to the hub but are not fixed to the syringe so that a variety of length and guages of needle cannulas are stored in one section which may contain about twenty various lengths and guages of needle cannulas; an inventory of about twenty or more of each guage and length of needle cannula may be stored in each section. There may be about ten sizes of syringes with about twenty or more of each syringe stored in a different section of the same locker. When a given quantity of a given medicament is required, the required size of needle cannula is fitted to the required syringe thereby combining the right length and guage of needle cannula with the right size of syringe.
All of the above mentioned safety syringe needle cannula inventions would require an inventory of about ten (10) times that of the present invention. Each needle cannula size would have to be fixed to each syringe size and each syringe size would have to be fixed to each needle cannula size and this would require an inventory of over a hundred needle cannula syringe combinations which would be multiplied by ten each; the numbers required for the necessary inventory on a given floor of a hospital would be astronomical. The need has developed for a safety needle cannula that will be a module apart from the syringe, that could be placed on any standard syringe.